1. Field of the Invention
This invention relates to a panel fastener system for securing a panel to a frame across an opening, and particularly relates to storm windows using a magnetic type fastening system which is easily installable and removable and maintains its integrity when subjected to the environmental conditions of use.
2. Prior Art
With the increase in the cost of energy for both heating and cooling and the recognition of the desirability to conserve energy, the art of insulating homes, in particular the insulating of existing windows and doors, is receiving continuing and increased attention. A substantial percent of the homes heat loss in the winter and heat gain in the summer is through glass panes of windows and doors. Traditional means of insulating against this loss or gain have included the use of heavy and expensive storm windows, the glass of which requires separate frames of wood or aluminum. However, windows of this type do not provide efficient insulating capability due to air infiltration into the conditioned zone. In addition windows of this type typically interfere with and detract from the beauty of the windows from both the inside and outside.
Another popular means of insulating the window area is the provision of insulating glass which is manufactured in multiple thicknesses of either two or three sheets, each separated by an air space from the other prior to assembly into the sash. While the insulating capabilities of glazing of this type are far superior to those of a single glass pane, the increased cost of multiple thickness glazing has discouraged its use in many instances. In addition, double glazing is impractical for windows which have an existing single pane, since the sash is not designed to accommodate the increased weight and thickness of the double glazed panels. Thus, although it has long been recognized that double glazed windows possess much greater insulating ability than single glazed windows, most installations have been provided with a single glazing for the sake of economizing on construction costs. Thus, it has become increasingly desirable to convert single glazing to double glazing, not only for improving the insulating properties, but also for the sake of advantages which may be obtained from the addition of a tinted or reflectively coated pane. Unfortunately, removing and discarding existing windows and installing double glazed units in its place is usually prohibitive in cost.
Thus, there have been developed numerous types of fastener systems for mounting either flexible or rigid glazing panels to existing window openings. Such fastener systems have met with varying degrees of success. Generally these systems may be divided into two categories: (1) glazing fastener systems which mechanically attach the glazing sheet to the frame of the window by mechanical clip means, e.g. velcro, frictional clips; and (2) glazing fastener systems which magnetically attach the glazing sheet to the frame. Numerous type systems exist for the first type, some of which are enumerated herein. However, the magnetic systems, were developed to overcome some of the problems associated with the mechanical type systems, in particular providing for the ease of installation and removal of the glazing sheet.
One type of magnetic glazing fastener system is depicted in FIG. 1, for example MAGNETITE magnetic storm window from Viking Energy Systems, Co., Hanover, Mass. It has been found that this type system has certain disadvantages which can be attributed to a combination of the environmental conditions the system is exposed to and the limitations of the system, per se, which result in improper sealing and insulation problems.
Referring to FIG. 1, this prior art system has a steel element (28) adhesively mounted at (30) along the length of the frame (22). The window opening (50) is provided with the conventional primary glazing sheet (24). This prior art system is further provided with a glazing retaining member (56) extending along and mounted to the edge of the glazing sheet (32). The retaining member (56) depicted has outer and inner legs (34, 36 respectively) which are connected to each other at one end. The edges of the sheet are retained and mounted therebetween. A rubber bound barium ferrite magnetic element (58), in extruded strip form, is mechanically mounted to the inner leg (36). The glazing sheet (32) having the glazing retaining member (56) surrounding it is then mounted to the steel element (26).
The disadvantages of this system can be appreciated in that the air insulation chamber (42) created by the glazing sheet (32) and the primary glazing sheet (24) can reach a temperature of up to 160.degree. F. due to the sunlight filtering through the primary glazing sheet (24). Such a high temperature creates a number of problems. The failure temperature of economically acceptable adhesives used to attach the steel element (28) to the frame (22) is typically about 175.degree. F. This means that even at 150.degree. F. the adhesive tends to soften and grow weak. Additionally the steel element (28) tends to expand less and at a different rate than the polymeric adhesive and carrier, e.g. PVC based tape. This stresses the adhesive bond. Additionally, the polymeric glazing sheet (32), and the glazing retaining member (56) tend to become soft and pliable upon heating. This causes the sheet (32) to sag due to its own weight resulting in the breaking of the magnetic and/or adhesive bond causing the window to sag and fall (see 60--FIG. 1). This is a safety hazard and can cause damage to the glazing fastener system. Many manufacturers of similar type magnetic frames are aware of this problem and provide clips which are placed around the perimeter of the frame. Such clips cost the consumer money and labor and detract from the overall appearance of the window. Additionally, such clips detract from the value of the system in being easily removable and installable.
Still further in order for the magnetic elements to attract each other properly to obtain maximum attachment force, e.g. 4 to 8 pounds of pull per linear foot, the magnetic elements must make flush contact with each other. Most windows are not perfectly square. Ridges, bumps, tapers, slants, etc., exist in the frame for a variety of reasons, e.g. the building settles, the frame shifts with climatic changes and age, wood warps, design reasons require a slight taper or bevel, wear causes sections of the casing to dislodge or shift slightly, etc. It is thus desirable to provide for these irregularities.
More specifically, there are numerous known types of storm windows and moldings, see for example the following U.S. Pat. Nos.:
2,219,699 to Owen; PA1 2,631,340 to Decker; PA1 2,780,846 to Lyon; PA1 3,133,324 to Foreman; PA1 3,175,603 to Tonnon; PA1 3,214,879 to Ellingson, Jr. et al; PA1 3,299,591 to Woelk; PA1 3,824,753 to Anderson; PA1 3,911,630 to Nally; PA1 3,955,331 to Williams; PA1 3,971,178 to Mazzoni et al; PA1 3,992,815 to Potter; PA1 4,021,980 to Wilfong; PA1 4,068,428 to Peterson III; PA1 4,069,641 to DeZutter; PA1 4,079,558 to Gorham; PA1 4,112,642 to D'Aragoni; PA1 4,134,240 to Bolonga et al; PA1 4,160,348 to Chapman et al; and PA1 4,194,331 to Gingle et al.
Of the aforementioned U.S. patents only the following describe the use of magnetic elements to mount the storm window to the sash or an element attached thereto:
Owen describes a double glazed window construction comprised of a sash, a pane of glass in the sash and a plurality of magnets secured at spaced intervals around the periphery of the sash. A second pane of glass is positioned within the sash and spaced from the first pane. Magnets and metallic means co-acting with the magnets releaseably secure the second pane of the glass to the sash. The metallic means described are a metallic retainer strip lying on the outer side of the second pane of glass having an annular frame of metal of substantially U-shaped cross section, which surrounds the pane of glass.
Foreman provides a weather stripping means around the entire perimeter of the sash of a double hung window while simultaneously providing anti-rattle window support and position control at all levels of window elevation. This is accomplished by means of a continuous pliable magnetic strip which is mounted along the entire length of three sides of the sashes. Cooperating with the magnetic strip is a magnetizable steel strip which is in aligned relationship thereto. The magnetic strip may be secured and positioned by the use of adhesives or by a pressed fit in a groove or slot shaped to accommodate the magnetic strip.
Anderson describes a storm sash and structure for installation of the storm sash on a prime window sash. The storm sash includes a generally "U" shaped dual durometer hardness plastic strips secured to a glazed panel around the periphery thereof.
Peterson, III describes an insulating window which includes a transparent, rigid sheet of plastic having spaced hook-and-loop fastening elements (Velcro) adhered thereto in areas about the margin of one face thereof. Complimentary spaced hook-and-fastening elements are attached to the inside window frame of a house. Weather stripping is attached directly to the same face of the sheet of plastic about the margin thereof to form a seal between the sheet of plastic and internal window casing frame.
Gorham describes an outer portion of rigid plastic and of generally U-shaped configuration. A transparent plastic is inserted into the open end of the U and the legs are spread sufficiently to firmly grip the pane material. This can be mounted to flat strips of magnetic material secured to the side and top facings by, for example, weather resistant cement. The inner and outer portions are joined by a central portion which is hollow and sufficiently resilient to compensate for irregularities. This system provides no rigidity for the pane material and the magnetic materials force is dissipated by the material which forms the central cavity and causes slippage between the surface and strip.
Gingle et al describes a system for double glazing existing panes and windows or the like wherein a pane of material is cut to the shape of the exposed surface of an existing window pane in its sash. The additional pane is secured to the existing pane through the use of magnetically intermatible spacer strips which are secured to the existing panes around their outer periphery by means of an adhesive. The intermatible spacer strips are of a thickness which allows for separation of the two panes by a sufficient distance to create an air space therebetween to enhance the insulating properties of the structure. A thin flexible strip of decorative material is secured to the surface of the attachable pane opposite the existing pane along its periphery so as to overlap the adhesive on the opposite face of the attached pane while extending outward to overlap the inside edges of the sash and thereby additionally seal and insulate the area around the outer periphery of the attached pane.